He said: ‘The family is threatened by a conception of human nature that is proven to be defective, … defending the family and life in society is prophetic and anything but regressive. Marriage and the family are institutions that must be promoted and defended from every possible misrepresentation of their true nature, since whatever is harmful to them will in fact be injurious to society itself.’

The Pope thus raised three points: Firstly saying that marriage between man and woman is a ‘fact’ of nature and ‘threatened’ by other forms of marriage which are ‘proven’ to be ‘defective’.

Secondly, he warned of that the consequences of legalising gay marriage would harm society, perhaps a critical reference to the right to adoption by same-sex couples.

Thirdly, by saying that ‘defending the family and life is propophetic’ and not ‘regressive’, he is in fact calling upon the French Catholic lobby not to shy away and take a more active stance against the government’s plans to introduce same-sex marriage.

This attack by the Pope is unprecedented in its tenacity and its direct call to interfere in the affairs of a government. His previous attack on the introduction of same-sex marriage in Spain was much more subdued and less strongly worded.

The conservative Catholic lobby in France has been very vocal in its opposition to the country’s government plans to introduce same sex marrige, although some Bishops have remained silent fearing to be portrayed as regressive.

Last week, Christine Boutin, the leader of France’s Christian Democratic Party and one of France’s most vocal conservatives, called for a referendum on the issue and warned of ‘heavy consequences for society’ if the law were to go ahead.

She was joined by the Catholic Cardinal of France, Philippe Barbarin who warned that same-sex marriage will lead to ‘a breakdown in society.

‘This could have innumerable consequences. Afterward they will want to create couples with three or four members. And after that, perhaps one day the taboo of incest will fall.’

At the same time, Dominique Rey, the Bishop of Fréjus-Toulon, stated that: ‘A referendum must be held to allow a real debate and to make sure the government is not in the grip of the lobbies.

‘A majority of the population agrees with the traditional view of marriage.’

However, according to a BVA French poll published in August, 65 percent of French people support gay marriage and 53 percent support adoption by gay couples.

The full draft of the bill to introduce same-sex marriage is expected to be presented to the French cabinet on the 31 October.